Looks like a parasol mushroom which is edible and very tasty but please be absolutely sure before you try it. http://en.wikipedia.org/wiki/Parasol_mushroomMake sure it ticks all the boxes on description, habitat etc. There is a similar looking one that gives you stomach problems!

I am almost certain it is a Prince Mushroom, Agaricus Augustus. These smell strongly of almond and are delicious. At six inches across, you have a small one. Also the time of year is right. They often fruit in June and September to October.

The mushroom you found is the fruit of a large fungus that lives underground. Keep your eye on the area you found it. THere will probably be more.

It may be subrufescens, but I don't think so. Augustus I've eaten lots of. Subrufescens I've only seen in pictures, but the caps seem more red on subrufescens, (which translates from latin as "below reddish").

The caps on augustus are golden brown like the picture provided. There is nothing really reddish about it. Note that both species along with the also similar A. smithii are all good edibles.

I found your signature quote poignant. If your quote is true as I believe it to be, I fear that the average person is so averse to learning that not much will be saved. The emotionally appealing species that people want to save are part of the same interdependent web of life as everything else. Paradoxically, the same people who are in favour of saving frogs might also favour extincting all their insect food items. Let them eat cake, I guess.

It saddens me that people only find warm and fuzzy animals worth saving, and not all life for its own sake.

Original poster is in California, toasty warm down in that state which subrufescens prefers and then there's the size which you caught already. Caps look to be a rusty red to me in the photos as opposed to a golden brown but that doesn't mean much. Regardless, you nailed it and it is definitely Agaricus and you nailed the other shroom id in the pot in the other thread.

Yes, emotionally appealing species have the advantage. What odd timing for you to mention this. Yesterday I was volunteering and we were all crowded into an out building where I had set out a few objects for the group to familiarize themselves with. Three younger boys ran off and filled the pockets of their jackets with gravel then ran back into the barn and began whipping them up toward some imaginary target. Boys will be boys. The behavior was ignored as I really didn't see anything they could destroy up there other than a poster of woodland creatures which looked as if it had seen better days and a broom could easily sweep up the gravel falling to the ground.

My vision isn't exactly what it used to be. The boys were whipping gravel at three big brown bats clinging to upper rafters. My heart sunk. Big brown bats are so tiny and so incredibly vulnerable. In my best authoritative mom voice, I yelled out "stop it right now". These kids are nothing but a by-product of the tv they watch and parents who are working and stressed making ends meet who most probably don't have as much time as they'd like or the past experiences to be able to instill a greater love of the natural world in their children. I don't blame the kids for trying to destroy something they had been taught to fear but it did need to stop. Once I had their attention, I asked them to please pick up all the gravel from the floor and instructed them to go out to the parking lot to get rid of it and reminded them to empty their pockets of gravel when they were out there too. I took a moment to frisk around for some pamphlets I thought we had on bats but they were gone (lack of funds to keep printed color pamphlets in stock) so I did an about face and began covering bat basics on my own. Pointed out the obvious that we had all been occupying the same space with no issues and that even after the bats were being stoned they hadn't swooped down to try to ward off their attackers. Lots of good questions were asked, some I could answer and some I couldn't. When we were leaving to begin our hike, one of the boys came up to me and said he was really sorry. I squeezed his little hand and let him know that even big people feared what they didn't understand and now that he knew the truth about bats, he could be a bat protector. Bat protector? Yup, bat protector. I told him that if he ever saw little people trying to hurt bats that he should go find an adult to get help for the bats. He said he would. One out of three made a connection yesterday. Not bad odds fish dr. Not bad odds at all

If your quote is true as I believe it to be, I fear that the average person is so averse to learning that not much will be saved.

I don't want to believe the average person is averse to learning... so I won't. I do believe there to exist many roadblocks though with the pursuit of the quick dollar and emotion having a distinct advantage over logic many times. Lots of misinformation floating around out there that is allowed to stand uncontested. And this, coming from a person who has a frog on her counter top right now in a mixing bowl with a dish towel draped over the top. We found it in a window well late last night and it was too dark to walk him down to release.

Here's another favorite quote of mine-

The tendency of man's nature to good is like the tendency of water to flow downwards.-Mencius